Yes, homophobia should be discouraged on JLU. So should be eating kittens and kicking babies.
While obviously concurring with the fact that homophobic behaviour (just like any other inappropriate or bigoted behaviour) is not welcome on JLU (and in fact, against the user terms), I completely fail to see the point of your post.
I have yet to notice a single outright homophobic comment anywhere on JLU. And while there might have been occasional snickering on random mature content-related topics (not specifically linked to discussions of homosexuality), none of what I have seen ever crossed the line from questionable taste into anything that demands action (and I am quite easy on the trigger with that one).
In fact, the post you link to is a model of restraint and I do not see a single out-of-line comment from any of the contributors there.
In conclusion, I really don't know what your motivations for this post are, but it looks more like strawman building than actual community contribution...